source: GTP/trunk/Lib/Vis/Preprocessing/src/ObjectPvs.cpp @ 2727

#include <iostream>
#include <stack>

#include "Mesh.h"
#include "ObjectPvs.h"
#include "Intersectable.h"
#include "IntersectableWrapper.h"
#include "KdTree.h"
#include "common.h"
#include "BvHierarchy.h"

// $$ switched off by JB for testing
#define USE_MULTIPLE_OBJECTS  0
using namespace std;


namespace GtpVisibilityPreprocessor {

static ObjectPvs dummyPvs;

/** the pvs is the number of different objects in the node leaves
        We eliminate already accounted kd nodes and objects using mailboxing. 
*/
static int EvalKdNodeContribution(KdIntersectable *kdobj)
{
        int pvs = 0;
        stack<KdNode *> tStack;

        tStack.push(kdobj->GetItem());

        while (!tStack.empty())
        {
                KdNode *node = tStack.top();
                tStack.pop();

                // already processed node (=> objects already in pvs)?
                //node->Mail();
                if (node->IsLeaf())
                {
                        KdLeaf *leaf = static_cast<KdLeaf *>(node);

                        // Objects already accounted for can only be found among those
                        // which are referenced in more than one leaf
                        ObjectContainer::const_iterator oit, oit_end = leaf->mObjects.end();

                        for (oit = leaf->mObjects.begin(); oit != oit_end; ++ oit)
                        {
                                Intersectable *obj = *oit;                                              

                                if (!obj->Mailed2())
                                {
                                        //if (dummyPvs.AddSample(obj, 1.0f))++ pvs;
                                        obj->Mail2();
                                        ++ pvs;
                                }
                        }
                }
                else // traverse tree
                {
                        KdInterior *interior = static_cast<KdInterior *>(node);

                        tStack.push(interior->mFront);
                        tStack.push(interior->mBack);
                }
        }

        ///return dummyPvs.Size();
        return pvs;
}


/** Returns the the number of new (unmailed) objects in the leaves of the node.
        We eliminate already accounted bvh nodes and objects using mailboxing. 
*/
static float EvalBvhNodeContribution(BvhNode *bvhObj)
{
        BvhNode *node;

        // hack for choosing which node to account for
        if (bvhObj->IsLeaf())
                node = static_cast<BvhLeaf *>(bvhObj)->GetActiveNode();
        else
                node = bvhObj;

        // early exit
        if (node->IsLeaf())     
        {       
                BvhLeaf *leaf = static_cast<BvhLeaf *>(node);
                // objects already accounted for
                if (leaf->Mailed())
                        return 0;

                leaf->Mail();
                return (float)leaf->mObjects.size();
        }                        

        // compute leaf pvs
        float pvs = 0;
        stack<BvhNode *> tStack;
        tStack.push(node);

        while (!tStack.empty())
        {
                node = tStack.top();
                tStack.pop();

                // already processed node (=> objects already in pvs)?
                if (!node->Mailed())
                {
                        node->Mail();

                        if (node->IsLeaf())
                        {
                                BvhLeaf *leaf = static_cast<BvhLeaf *>(node);

                                // add #objects exclusivly in this node
                                pvs += (float)leaf->mObjects.size();
                        }
                        else // traverse tree
                        {
                                BvhInterior *interior = static_cast<BvhInterior *>(node);

                                tStack.push(interior->GetFront());
                                tStack.push(interior->GetBack());
                        }
                }
        }

        return pvs;
}


float ObjectPvs::EvalPvsCost() const
{
        float pvs = 0;

        Intersectable::NewMail2();
        
        ObjectPvsIterator pit = GetIterator();

        while (pit.HasMoreEntries())
        {               
                Intersectable *obj = pit.Next();

                switch (obj->Type())
                {
                        case Intersectable::KD_INTERSECTABLE:
                                {
                                        // found kd node
                                        KdIntersectable *kdObj = static_cast<KdIntersectable *>(obj);
                                        pvs += EvalKdNodeContribution(kdObj);   
                                        break;
                                }
                        case Intersectable::BVH_INTERSECTABLE:
                                {
                                        BvhNode *bvhObj = static_cast<BvhNode *>(obj);
                                        pvs += EvalBvhNodeContribution(bvhObj);
                                        break;
                                }
                        default:
                                // hack: should use assigned cost here
                                ++ pvs;
                                
                                break;
                }
        }

        return pvs;
}


}